板料冲压连接成形机理及成形力分析

Analysis of deformation mechanism and forming force for sheet clinched joint

以有限元分析软件Deform-2D为平台,建立了板料冲压连接有限元模型,对板料冲压连接成形过程进行了分析研究。结果表明:在板料冲压成形过程中,S形颈部主要是由于板料的流动速度不一致而形成的;成形过程可以分为准备压入阶段、前期成形阶段、凹模凹槽填充阶段、保压阶段4个阶段;成形过程中,冲压连接所需要的冲压力呈阶段性持续增加,压边力在成形开始阶段基本保持不变,在凹模凹槽填充阶段,压边力有所下降,保压阶段,压边力迅速增加。研究表明,连接点的抗拉强度和剪切强度分别为112和550 MPa,均符合连接强度要求。

Based on the FEM software of Defrom-2D, the model and forming processing of sheet clinched joint were respectively built and analyzed. The results show that the cause for forming of S-neck is the different forming velocities of sheet during the process of sheet clinched joint. The forming process includes four stages, that is stage of prepared punching, stage of pre-forming, stage of die groove fill- ing and stage of holding pressure. During forming process, the forming force required for clinched joint periodically and continuously increases. While the blank holder force is basically unchanged at the stage of initial forming, to some extent declines at the stage of die groove filling, and sharply rises at the stage of holding pressure. The experimental results show that the shear strength and tensile strength are 112 and 550 MPa respectively, which meet the requirement of joint strength.